First of all very nice job on the mobile app! There's still room for improvement, but it's by far the best iPad app in it's category.
The features that I would like to see in the new version are:
persistent tool selection - specifically, I do a lot of pixel art work, which means I use the pixel brush. However, every time I need to use the Selection persona, I come back to the brush tool being reset to it's default tool, the paint brush. This is quite annoying as I always have to tap 2 times just to go back to the brush I was using. If Affinity would remember I selected the pixel brush my workflow would be much improved
switching personas and having personalized menus on 2-finger tap is cool, however, once I make a selection and go back to the drawing persona to move/resize/draw something I cannot access the Select menu without having to switch back to the Select persona. Most of the times I just need to deselect all, so having to tap 3 times is frustrating. I would like to have an option to deselect without switching personas. Maybe long press on the Select persona button in the toolbar gives me the Select menu without switching, maybe 2-finger tap includes some selection items as well even in the default drawing workspace.
the fill color I feel should be the color that you're drawing with, not a different one. This is a standard in all drawing software and it's a logical implementation of real life painting - you use your brush to paint small areas, you dump the whole bucket of paint to fill in a large area. Having 2 active colors is nice, but the ability to switch between them and have a primary one which all tools use makes more sense than arbitrarily assigning different colors to different tools.
Keep up the awesome job!